1. Field of the Invention
The present invention relates to a simulation technique for support of the design of image forming apparatuses.
2. Description of the Related Art
Conventionally, conveyance of sheet-like materials is performed in many fields. For instance, with an image forming apparatus, conveyed material such as printing material is conveyed by a conveyance mechanism including a roller, a guide and the like. Control software is essential in conveying conveyed material. In many conveyance controls, conveyed material is rarely conveyed at a constant speed and in one direction. Normally, the conveying speeds of conveyed material are appropriately switched. For instance, when a sensor detects a position of a conveyed material, a conveyance control unit may stop the conveyed material at a predetermined position or may reverse a roller to invert the conveyance direction.
In addition, sales points of recent image forming apparatuses are many functions and high productivity. Accordingly, software for controlling image forming apparatuses is becoming increasingly complex, resulting in an increase in man-hours required for discovery, cause identification and correction of failures.
In such circumstances, there are more opportunities to use simulation techniques in the design of conveyance mechanisms. In Japanese Patent Laid-Open No. 9-81600, a system is proposed which detects potential defects in a conveyance mechanism by performing simulation operations on the behavior of conveyed material.
With the active use of mechanism simulations in every conceivable situation, demand is increasing for techniques to verify the correctness of software with such control mechanisms. With software verification, simulations of basic paper behavior or reproductions of irregular situations are essential. It is empirically known that design errors in software occur more often in areas that control irregular behavior than in areas that control basic behavior.
In Japanese Patent Laid-Open No. 5-143260, a design support method is proposed in which an input apparatus such as a keyboard causes printer control software to generate an external event such as turning a switch on or off, or opening or closing a cover.
In conventional simulators for software verification, the execution speed of a simulation is constant. This is considerably inconvenient, since execution speeds cannot be changed according to intended purposes.
For instance, when it is desired to execute a wide-range simulation in which operation is performed in various modes, using a higher simulation speed than normal will produce faster results and is therefore efficient. On the other hand, when it is desired to perform rigorous verification on a phenomenon in order to verify true characteristics thereof, the phenomenon may be analyzed with greater detail by reducing its relative simulation speed.